Most injuries of the cervical spine are soft tissue injuries, due to low-energy impacts from rear-end collisions. The accident victims with soft tissue injuries have been known to have residual pain for many years after the accident. Less frequent, but more severe are neck injuries due to frontal and side collisions. The overall objective of the proposed research is to provide a better understanding of these injuries. The available research studies have used volunteers, whole cadavers, anthropometric dummies, and mathematical models to simulate the injury-causing events. The traumatic event in these experiments is studied from outside and not at the site of injury in the cervical spine. The uniqueness of the proposed research lies in its ability to directly study the site of injury during the trauma. Fresh cadaveric human cervical spine specimens (occiput to T1) will be utilized. The specimen is provided with an appropriate head surrogate. The specimen is stabilized with the help of compression springs simulating overall muscle function. The trauma is produced in a specially constructed apparatus where the acceleration at the base of the specimen, i.e. the T1 vertebra, is simulated to be similar to that documented in real life car crashes. Radiographs are taken, and multidimensional instability is measured before and immediately after the traumas. During the trauma, loads at occiput and T1, accelerations of the head, intervertebral motions, and deformations of the ligaments and vertebral artery are continuously measured. After the trauma, CT scan and MRI are performed, and the specimen is dissected and the injuries to the soft tissues and bones are described and quantified. The investigators propose to study four traumas: rear-impacts with head-forward and head-turned to side, and frontal and side impacts. Injury thresholds and injury mechanisms for low and moderate energy traumas will be determined. The significance of the research lies in helping provide better understanding of the mechanisms of low-and moderate energy traumas to the cervical spine. Significant advances can be made in prevention of these injuries by designing optimal automotive seats and safety equipment; in diagnosis by developing radiographic tests that are more sensitive to soft tissue injuries; and, in treatment by better assessment of the anatomic injuries and multidirectional instabilities.